Width vs height

hullo.
im still looking how to maintain max. stage width and height. i have managed to achieve it on the width, but for some reason have been unable to do it for the height. that is, i have managed to make a line go from one side to the other (almost) but cant figure out how to do it on the vertical.
zbot is the horiz line at the botton
ztop for the one above
the problem, is for xleft (the vertical lineon the left)
i have included what i think to be the nearest code yet, and a fla.

 
Stage.align = "LT";
Stage.scaleMode = "noScale";
bg._width = System.capabilities.screenResolutionX-20;
bg._height = System.capabilities.screenResolutionY-70;
bg.onResize = function() {
this._x = (Stage.width-this._width)/2;
this._y = (Stage.height-this._height)/2;
};
Stage.addListener(bg);
zbot._x = 62;
zbot.onResize = function() {
this._width = Stage.width;
};
Stage.addListener(zbot);
////
xleft._x = 270;
xleft.onResize = function() {
this._height = Stage.height;
};
Stage.addListener(zbot);
////
ztop._x = 62;
ztop.onResize = function() {
this._width = Stage.width;
};
Stage.addListener(ztop);
// get the content clip to stay fixed horizontally centred
content.onResize = function() {
this._x = (Stage.width-this._width)/2;
};
Stage.addListener(content);
// manually invoke the onResize events for the clips to start things off
bg.onResize();
zbot.onResize();
ztop.onResize();
xleft.onResize();
content.onResize();